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Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The kinetic energy needed to project a body of mass m from earth surface to infinity is 1/2 mgR, where R is the radius of earth. Reason R: The maximum potential energy of a body is zero when it is projected to infinity from earth surface. In the light of the above statements, choose the correct answer from the options given below.

1. A is true but R is false
2. A is false but R is true
3. Both A and R are true but R is NOT the correct explanation of A
4. Both A and R are true but R is the correct explanation of A

Correct answer: A is false but R is true

Solution

Assertion A is incorrect because the kinetic energy required to project a body to infinity is actually equal to the gravitational potential energy at the Earth's surface, which is given by GMm/R, not 1/2 mgR. Reason R is correct as the potential energy approaches zero when an object is at an infinite distance from the Earth.

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